Low-dose ondansetron with dexamethasone more effectively decreases vomiting after strabismus surgery in children than does high-dose ondansetron.

Background: Ondansetron and dexamethasone have been observed to decrease the incidence of vomiting by children after general anesthesia. This study compared the effect of high-dose (150 microg/kg) ondansetron with low-dose (50 microg/kg) ondansetron plus 150 microg/kg dexamethasone on the incidence of vomiting after strabismus in children.
Methods: This study had a double-blind, blocked, stratified, randomized design. With parental consent and Hospital Ethics Committee approval, healthy children aged 2-14 yr who were undergoing elective strabismus surgery were studied. Anesthesia was induced intravenously with propofol or by inhalation with halothane and nitrous oxide. Patients in the high-dose group were given placebo plus 150 microg/kg (maximum dose, 8 mg) of ondansetron intravenously, whereas patients in the low-dose group were given 150 microg/kg dexamethasone (maximum dose, 8 mg) and 50 microg/kg ondansetron intravenously in a double-blind manner. Anesthesia was maintained with halothane and nitrous oxide. All incidences of vomiting occurring as long as 24 h after anesthesia were recorded.
Results: Three of the 200 patients enrolled in the study were excluded from data analysis. The groups were similar with respect to demographic data and potential confounding variables. Patients vomited from 0-12 times. The low-dose ondansetron plus dexamethasone group had a lower incidence of vomiting, 9% (95% CI = 4-17%) versus 28% (95% CI = 20-38%; P < 0.001). Only 1% of the patients in the low-dose ondansetron plus dexamethasone group vomited while in the hospital.
Conclusions: Low-dose ondansetron plus dexamethasone is an effective prophylactic antiemetic combination for children undergoing strabismus surgery.